The present invention pertains to heat exchangers for flowing fluid materials and, more particularly, to a heat exchanger of a corrugated tubular construction in which a stationary turbulator plate is disposed within each corrugation to improve the heat exchanging contact between the fluid and the walls of the conduit.
The prior art discloses the use of heat exchangers in which the tubular outer wall of the conduit containing the fluid flow is corrugated. Typically, each of the corrugations is provided with an interior baffle plate which blocks direct flow of the fluid through the conduit and causes the fluid to be diverted from a purely axial flow. The diversion of fluid flow by the baffle plate slows the flow through the conduit somewhat and enhances the heat exchanging contact between the fluid and the walls of the conduit, the surface area of which is substantially enhanced by the corrugated construction.
U.S. Pat No. 3,099,315 shows a heat exchanger including a corrugated main tubular conduit in which each corrugation comprises a pair of concave disks attached at their outer peripheral edges to define a corrugation with an open interior and opposite axial openings for the flow of a fluid therethrough. An interior baffle plate is enclosed in each corrugation and is provided with radially offset aperatures to allow fluid to flow from one side of the baffle plate to the other after it is diverted from a purely axial direction. Each baffle plate also includes a series of stationary vanes which serve to direct the axial flow of fluid into the corrugation radially outwardly to the holes in the baffle plate. Apart from the upstanding vanes, the interior surfaces of the corrugations and baffle plates are essentially smooth and uninterrupted.
U.S. Pat. No. 2,030,734 discloses a heat exchanger for a furnace which includes a series of axially connected heat exchanging chambers of annular construction, each of which encloses a baffle plate disposed to block direct axial flow and having an opening around its radial outer edge to direct the axial flow into the corrugation from the center radially outwardly around the outer edge, and then back to the center of corrugation on the opposite side of the baffle to exit axially therefrom. A series of stationary vanes is used to attach each side of the baffle plate to the inside walls of the annular chamber and to impart a swirling movement to the air flowing through the chamber.
British Patent No. 2,354 shows a heat exchanger with annular chambers similar to those described in the foregoing patent. Each chamber includes a baffle plate which is attached between the outer walls of the annular chamber and has holes for the flow of fluid therethrough which are radially displaced from the axis of the heat exchanger. The interior heat exchanging surfaces of the annular chambers are generally smooth and uninterrupted.
U.S. Pat. No. 4,561,494 shows an oil cooling heat exchanger comprising a series of axially aligned heat exchanging units also defining a generally corrugated construction. Each unit comprises a pair of outer dish-shaped plates which enclose a double layer internal baffle plate, each of which baffle plates is provided with stamped strands displaced from the surface of the baffle plate to space the same from the interior walls of the unit in which it is disposed, to provide contact surfaces for brazing the baffle plates in position, and to create turbulence in the oil flowing therethrough. The entire structure is intended to be enclosed in an outer housing through which a coolant, such as from an engine cooling system, is circulated to remove heat from the oil.
In order to optimize the heat exchanging characteristics of a heat exchanger utilizing stationary turbulator/baffle plates, it is important to maximize the heat exchanging surface area within the allowable volume provided for the unit and to create adequate turbulence in the flow to further enhance heat exchanging contact between the fluid and the heat exchanging surfaces. In addition, where the heat exchange is enhanced by the flow of a second fluid across the outside surface of the conduit through which the primary flow of the fluid occurs, it is also desirable to increase the heat exchanging surface area and to additionally provide for turbulence in the flow of secondary fluid.